For a wide range of medical reasons, medical catheters, medical surgical devices such as therapeutic devices, and electrical sensing and/or stimulation electrode bearing leads are introduced into a patient's body either temporarily or chronically for monitoring and/or therapeutic operations. In many of the medical applications for these devices, it is necessary to precisely locate a structure at or near the distal end of the catheter or lead body in relation to specific body tissue in a body cavity or vessel.
In the magnetic resonant imaging (MRI) industry, active marker detection has become a growing interest. With the powerful magnetic field of an MRI system, a conventional method includes a circuit having an RF coil, a capacitor, and resistor. Such a circuit is attached to the end of a catheter for use in coronary dilation procedures or where guide wire applications are necessary.
Typically, the conventional methods of active marker detection use insulated wires or photo illumination to excite the RLC circuit. However, this method may potentially harm the patient when an insulated wire extends the full length of the catheter or the bulkiness of a detuning photo-resistor may make interventional procedures virtually impossible. Thus a better design and methods are desirable.